The present invention relates generally to surgical clamping devices of the type used to occlude or otherwise seal off tubular structures, such as intestines, during surgical procedures. More particularly, the present invention relates to surgical clamping devices which can occlude tubular structures under uniformly distributed clamping pressure, thereby preventing leakage of matter therethrough.
At some point during most intestinal operations, it is necessary to actually open the intestine and expose the intestinal lumen, the interior channel of the intestine. To prevent the escape of intestinal contents, the surgeon usually places a clamp (e.g. an intestinal forcep) across the intestine above and below the area that will be opened. A variety of forceps are available for this purpose, including the Kocher, the Mayo-Robson and the Doyen intestinal forceps. Like conventional forceps, these clamping devices operate in a scissor-like fashion. One principal shortcoming with such types of clamping devices is that, when conventional forceps open with a pivotal movement, they are not in parallelism in the clamped position on the tubular structure. Thus, one side of the vessel may be damaged by pinching it excessively hard in order to completely occlude the opposite side thereof.
The existing intestinal forceps have several other characteristics which make them unsatisfactory to a large number of practicing surgeons. These instruments are all approximately 10 inches in length, 5 inches of which are the handles. This excessive length causes the instruments to be unwieldy and to obstruct the surgeon's work area while they are being used. In addition, the clamping pressure distribution provided along the clamping members of the forceps is not uniform, as illustrated in FIG. 1A.
Although this type of clamp is considered to be "atraumatic" and is intended to occlude the intestine without injuring it, in actual use these instruments are quite capable of traumatizing the intestinal tissue which they clamp, the result of which is to cause tissue cells to die. In an effort to reduce the amount of trauma caused by these clamps, many surgeons slip pieces of soft rubber tubing over the clamp members. This practice is so widespread that the generally recognized name for these intestinal forceps is "rubber shods".
These problems have led surgeons to look for other ways to occlude the intestine more effectively and efficiently.
Similarly, in other types of surgical operations, a considerable number of spring clips are required to occlude severed blood vessels as well as for other purposes. The most common type of spring clip has smooth surfaced swinging jaws which are parallel when closed upon themselves but which are not parallel in the partially spread position that they assume on a blood vessel. While such types of spring clips can completely occlude a blood vessel to stop bleeding, such clamping devices based on the "parallel jaw-member principle" are not suitable where the tubular structure is larger than blood vessels, for example, when the tubular structure has the dimensions of an intestine. This is because the clamping members of these types of clamping devices (i) deflect away from their parallel arrangement when an intestine is clamped therebetween, (ii) the jaws tend to slip off the intestine, and (iii) a non-uniform distribution of clamping pressure is exerted on the intestine while clamped between the deflected almost parallel jaws. This non-uniform distribution of clamping pressure is illustrated in FIG. 1B.
Prior art surgical clamping devices also suffer from inadequately designed jaw teeth, which while designed to resist slippage of the jaws on the vessel, consequently exert dissimilar force components on the vessel (i.e. the intestine) at different locations. Specifically, the occluding (i.e. clamping) pressure is not uniformly distributed, and consequently causes trauma to the intestinal tissue, the result of which can be to cause the tissue cells to die.
Various high frictional clamping surfaces have been used by prior art devices, and nearly all of such surfaces include interlocking jagged or sharp edges or teeth which penetrate or unduly deform intestinal tissue and cause trauma thereto. In short, prior art clamping surfaces create high surface pressure locations which, while securing the intestine within the clamping device, create the serious problem of traumatization to intestinal tissue and the like.
In view of the above-described problems in the surgical clamping arts, a variety of prior art surgical clamping devices exist and are known to be useful in a variety of surgical settings, yet fail to provide an effective solution to such problems. Examples of such surgical clamping devices can be found in prior art U.S. Pat. Nos. 4,324,248; 4,407,285; 3,510,923; 3,509,882; and 3,506,012, which will be briefly summarized hereinbelow.
U.S. Pat. No. 3,509,882 to Blake discloses a parallel jaw spring clip. As illustrated, two opposed jaws are each molded integrally with the inner ends of two telescopic members. One member is disclosed as being a plunger and the other member as a barrel for the plunger. A metal compression spring is contained within the plunger and barrel, and is seated on a cap. Another cap having a spring guide pin is secured in the upper end of the barrel. The upper end of the spring is positioned against the cap and is secured in the upper part of the barrel to urge the jaws toward a closed position. Thus, the jaws are separable by pinching the opposed caps, and will come back in contact with one another when the pinching pressure is relieved. However, despite the parallelism in the jaws, when there is no intestine or similarly large tubular structure therebetween, the parallel surfaces of the jaw deflect under load (e.g. clamping an intestine), and thereby change the clamping pressure along the jaws. Consequently, under loading, the clamping pressure is not uniform along the jaws from the proximal to the distal end thereof. Also, due to the resultant clamping pressure distribution and the parallel jaw closing movement and clamping configuration, there is a tendency for the jaw members to slip off the vessels to be occluded. In addition, the serrated teeth on the jaws, while creating frictional forces between the vessels and jaws, result in high pressure locations, (thus a non-uniform pressure distribution along the cross section of the jaw members), and therefore have a tendency to cause trauma to tissue.
U.S. Pat. No. 3,510,923 to Blake discloses a parallel jaw ratchet clip having two jaws which remain in parallelism throughout their opening and closing movements. The jaws are mounted on two relatively slideable members which are pinched closed in accordance with the clamping force desired by the surgeon. A ratchet device holds the jaws closed and pinch grips are provided to release the ratchet device and open the jaws. A retractor is similarly constructed but has jaws equipped with hooks instead of teeth and the ratchet action is reversed to hold the jaws open instead of closed. This surgical clamping device, however, has several significant shortcomings and drawbacks, as well. In particular, despite the parallelism in the jaws when there is no intestine clamped therebetween, the parallel surfaces of the jaw deflect under load (e.g. clamping down on an intestine), and thereby change the clamping pressure along the jaws. Consequently, under loading, the clamping pressure is not uniform along the jaws from the proximal to the distal end thereof. Also, due to the resultant clamping pressure distribution and the parallel closing movement and clamping configuration, there is a tendency for the jaw members to slip off the vessels to be occluded. In addition, the serrated teeth on the jaws, while creating frictional forces between the vessels and jaws, result in high pressure locations, (thus a non-uniform pressure distribution along the cross section of the jaw members), and therefore have a tendency to cause trauma to vessel tissue.
U.S. Pat. No. 4,324,248 to Perkin discloses a microsurgical clip for clamping small blood vessels. The microsurgical clamp includes a hollow shell having top and bottom openings with an integral clamping element (i.e. "duck bill") extending forwardly from the lower edge of its front wall. A cooperating insert of an inverted "U" shape is nested in the housing to define a central pocket and terminates in a clamping element which cooperates with the duck bill of the hollow shell. The shell and the insert have their back walls hinged together, and an expansible spring is seated in the pocket with one end coupled to the shell and the other end coupled to the insert for urging the insert upwardly into the shell to bias the clamping elements together. The insert has a crown which projects upwardly through the opening at the top of the shell so that, upon application of pinching pressure, the insert is pressed downwardly with respect to the shell to compress the spring and to spread the clamping elements for clamping engagement of a blood vessel therebetween. However, as a result of the scissor-like operation of the clamping elements, the clamping pressure is not uniform along the clamping elements from the proximal to the distal end thereof. Also, due to the resultant clamping pressure distribution and the closing movement of the clamping elements and clamping configuration, there is a tendency for the clamping elements to slip off the vessels or other tissue. In addition, without any special provision for a gripping surface to create frictional forces between the vessels and jaws, clamping elements having exceedingly high clamping pressures must be used. Thus, while not necessarily creating a non-uniform pressure distribution along the cross section of the clamping elements, there is nevertheless a great tendency to cause trauma to vessel tissue, the result of which cause the cells thereof to die. In addition, such clamping device is wholly unsuitable for occluding intestines.
U.S. Pat. No. 4,407,285 to Perkin discloses a microsurgical clip for clamping small blood vessels, as for example, during brain surgery or the like. The microsurgical clamp includes a hollow shell of generally rectangular shape having opposed side walls and a front wall, the shell having a clamping element (i.e. duck bill) or jaw, extending forwardly at the lower edge of the front wall. A cooperating insert of zigzag shape nested in the shell includes a top wall, front wall and clamping element, the insert being hinged between the side walls. An expansible spring is seated between the bottom wall of the shell and the top wall of the insert for biasing the clamping element into resilient clamping engagement. The hinge connection includes a hinge pin extending between the side walls at the upper back corners encircled by a tab bent at the end of the top wall of the insert. The side walls are angled downwardly from the hinge pin and the front wall of the shell is foreshortened so that, when the clamping elements are in clamping engagement, the insert projects upwardly beyond the shell. When the projecting insert is pinched downwardly by the finger tip, the spring is compressed accompanied by relative spreading of the clamping elements for engagement of a blood vessel therebetween. One of the features of the construction is that the back of the shell is open to provide a spring access opening for insertion of a selected spring to produce a predetermined degree of clamping force.
However, this clamping device, as with the one disclosed in U.S. Pat. No. 4,324,248, also suffers from similar shortcomings and drawbacks. Thus for example, owing to its scissor-like operation, the clamping pressure is not uniform along the length of the clamping elements, and also due to the closing movement of the clamping elements, there is a tendency for the clamping elements to slip off. In addition, the clamping force required to secure the clip onto a vessel is usually so large that trauma to tissue results. Moreover, this clamping device is wholly unsuitable for occluding intestinal lumen.
In view of the above surgical clamping devices, it is apparent that the prior art has not shown or even hinted how to achieve a surgical clamping or occluding device with a combination of features which includes (i) a clamping mechanism providing a truly uniform clamping pressure distribution along the length of the clamping members or jaws; (ii) an anti-slip clamping mechanism and/or jaw clamping surface which prevent vessels and tubular structures from slipping out of the clamping device during surgical operations, without the requirement of excessive tissue-traumatizing clamping pressures; (iii) jaw clamping surfaces which provide a uniform clamping pressure along the width-wise dimension of the clamping members and thereby prevent trauma to vessel tissue; (iv) a thumb-operable lock-open and release mechanism for easier and quicker application; (v) minimum size so as not to obstruct the surgical procedure; and (vi) manufacturability using light weight materials, having extraordinary degrees of reliability.
Accordingly, it is a primary object of the present invention to provide a surgical clamping device having a handactuatable clamping mechanism which provides a truly uniform clamping pressure distribution along the entire length of the clamping members or jaws.
Another object of the present invention is to provide a surgical clamping device having first and second clamping members, each with jaws which move from the open position to the closed position by the distal ends (i.e. tips) of the jaws meeting first, and then the jaws forceably moving towards each other reaching a parallel position when the spring force of the clamp is in equilibrium with the force of the closed intestinal lumen, wherein the distal tips of the clamping surfaces are closer than the proximal clamping surfaces, but are equally spaced when clamping is completed. As a result of this anti-slip clamping mechanism, a tubular structure such as an intestine can be completely occluded between the jaws under a uniformly distributed clamping pressure, and prevented from slipping out during surgical operations.
It is a further object of the present invention to provide such a surgical clamping device providing a uniform clamping pressure along the width-wise dimension of the clamping members and thereby prevent slippage of the clamp and trauma to vessel tissue.
An even further object of the present invention is to provide such a surgical clamping device which accomplishes complete occlusion of the vessel, is light in weight, disposable and inexpensive to manufacture.
Other and further objects of the present invention will be explained hereinafter, and will be more particularly delineated in the appended claims, and other objects of the present invention will hereinafter become apparent to one with ordinary skill in the art to which the present invention pertains.